1. Field of the Invention
This invention relates to a method for synthesizing crystalline organosilicate zeolites requiring a reaction mixture for crystallization thereof which contains magadiite as a source of silicon oxide.
2. Description of the Prior Art
Natural and synthetic zeolitic materials of the molecular sieve type are known and are staple items of commerce. High silica zeolites are extremely well known in the art and have been the subject of much attention in both the patent and technical literature. These materials have been demonstrated to have catalytic properties for various types of hydrocarbon conversions.
As a group, these highly siliceous materials are exemplified by U.S. Pat. Nos. 3,941,871; 4,061,724; 4,073,865; 4,104,294; 4,456,582; wherein the materials are prepared from reaction solutions which involve no deliberate addition of aluminum. However, trace quantities of aluminum are usually present due to the impurity of the reactants.
As is set forth in the above-identified U.S. patents which are incorporated totally herein by reference, these types of zeolites are prepared from a forming solution containing water, a source of quaternary ammonium cations, an alkali metal, a source of silica, with or without added alumina and with or without the presence of additional metals. As is known in the art, the forming solution is held at elevated temperatures and pressures until the crystals are formed and thereafter the zeolite crystals are removed.
Prior art sources of silica in preparing zeolites include sodium silicate, colloidal silica, silica hydrosol, silica gel and silicic acid.
A considerable amount of effort has been made to find cheaper routes to zeolites and to find ways to prepare purer forms of the zeolites, i.e., to reduce the quantities of aluminum present as impurities.
It has now been found that magadiite in its alkali metal form or in the hydrogen form, especially when made synthetically, is a particularly attractive source of silica as it enables useful zeolites to be prepared cheaply, easily and in a more purer form.